The singer — who’s married to actor Josh Duhamel — was spotted riding the newly relaunched Ghostrider ride July 14 with her sister, Dana, and had a sweet moment with Axl, 2, later in the day while cuddling up to Snoopy.

“Axl loved playing with Snoopy,” says a source, who adds that the trio also stopped in to dine at Ghost Town Grill.

“Ferg is right in the middle of shooting a video, so it’s going to be a pretty low-key Mother’s Day,” Duhamel, 43, told PEOPLE while attending the Kentucky Derby Saturday with G.H. Mumm champagne.

Between both of their schedules, the actor says he and his pop star wife have been “crazy busy” for the last couple of weeks and are looking forward to enjoying some quiet family time with son Axl, 2.

“I [asked her], what do you want to do? We got the whole day off,” said Duhamel, 43. “She said: ‘I just want to order some food in, and be with you and Axl.’ We’re just going to sit at home and just be a family.”

“It’s going to be nice just to have a very low-key, at home, Mother’s Day,” Duhamel said. “We’ll probably order in from someplace fancy, but that’s about as extravagant as we’ll get.”

“[Axl] looked at me the other day and he goes, ‘Daddy, you’re a good guy,’ and I go, ‘Thank you, Axl. You’re a good guy, too!’ ” Duhamel told PEOPLE about his and Fergie‘s hilarious offspring at the Los Angeles press day forLost in the Sun on Tuesday. “And he goes, ‘No, I’m Axl. I’m a boy.’ ”

Duhamel, 42, continues, “He sees a guy as a grown man and he doesn’t see himself as that, so he’s still a boy.”

Luckily for the actor and his songstress wife, Axl’s terrible twos have been quite the breeze, thus far.

“He’s pretty good,” says Duhamel of Axl, who celebrated his second birthday in August. “He’s got his moments, but like I said, he’s a very sweet natured, kind, happy little guy.”

Josh Duhamel‘s son may not have all his teeth yet, but he sure has developed a sweet tooth!

“[He’s] discovered candy, which we’re hoping to stay off as long as possible,” the actor tells PEOPLE of 22-month-old sonAxl Jack‘s new-found obsession that he and wife Fergie, 40, are attempting to monitor and “only trying to give him on special occasions.”

The couple aren’t always successful, though! “When my sister and my friends are in town and they see him, that’s the first thing they do to try to win his favor,” Duhamel, 42, explains.

As Axl morphs from a baby to a toddler (cue the tears), “every day there seems to be something,” the actor, who recently starred on Battle Creek, reveals. “He’s been counting and singing his ABCs.”